/**
 * This jQuery plugin displays pagination links inside the selected elements.
 *
 * @author Gabriel Birke (birke *at* d-scribe *dot* de)
 * @version 1.2
 * @param {int} maxentries Number of entries to paginate
 * @param {Object} opts Several options (see README for documentation)
 * @return {Object} jQuery Object
 */
jQuery.fn.pagination = function (maxentries, opts) {
	opts = jQuery.extend({
		items_per_page: 10,
		num_display_entries: 10,
		current_page: 0,
		num_edge_entries: 0,
		link_to: "#",
		prev_text: "Prev",
		next_text: "Next",
		ellipse_text: "...",
		prev_show_always: true,
		next_show_always: true,
		callback: function () {
			return false;
		}
	}, opts || {});

	return this.each(function () {
		/**
		 * 璁＄畻鏈€澶у垎椤垫樉绀烘暟鐩�
		 */
		function numPages() {
			return Math.ceil(maxentries / opts.items_per_page);
		}
		/**
		 * 鏋佺鍒嗛〉鐨勮捣濮嬪拰缁撴潫鐐癸紝杩欏彇鍐充簬current_page 鍜� num_display_entries.
		 * @杩斿洖 {鏁扮粍(Array)}
		 */
		function getInterval() {
			var ne_half = Math.ceil(opts.num_display_entries / 2);
			var np = numPages();
			var upper_limit = np - opts.num_display_entries;
			var start = current_page > ne_half ? Math.max(Math.min(current_page - ne_half, upper_limit), 0) : 0;
			var end = current_page > ne_half ? Math.min(current_page + ne_half, np) : Math.min(opts.num_display_entries, np);
			return [start, end];
		}

		/**
		 * 鍒嗛〉閾炬帴浜嬩欢澶勭悊鍑芥暟
		 * @鍙傛暟 {int} page_id 涓烘柊椤电爜
		 */
		function pageSelected(page_id, evt) {
			current_page = page_id;
			drawLinks();
			var continuePropagation = opts.callback(page_id, panel);
			if (!continuePropagation) {
				if (evt.stopPropagation) {
					evt.stopPropagation();
				} else {
					evt.cancelBubble = true;
				}
			}
			return continuePropagation;
		}

		/**
		 * 姝ゅ嚱鏁板皢鍒嗛〉閾炬帴鎻掑叆鍒板鍣ㄥ厓绱犱腑
		 */
		function drawLinks() {
			panel.empty();
			var interval = getInterval();
			var np = numPages();
			// 杩欎釜杈呭姪鍑芥暟杩斿洖涓€涓鐞嗗嚱鏁拌皟鐢ㄦ湁鐫€姝ｇ‘page_id鐨刾ageSelected銆�
			var getClickHandler = function (page_id) {
				return function (evt) {
					return pageSelected(page_id, evt);
				}
			}
			//杈呭姪鍑芥暟鐢ㄦ潵浜х敓涓€涓崟閾炬帴(濡傛灉涓嶆槸褰撳墠椤靛垯浜х敓span鏍囩)
			var appendItem = function (page_id, appendopts) {
				page_id = page_id < 0 ? 0 : (page_id < np ? page_id : np - 1); // 瑙勮寖page id鍊�
				appendopts = jQuery.extend({
					text: page_id + 1,
					classes: ""
				}, appendopts || {});
				if (page_id == current_page) {
					var lnk = jQuery("<span class='current'>" + (appendopts.text) + "</span>");
				} else {
					var lnk = jQuery("<a>" + (appendopts.text) + "</a>")
						.bind("click", getClickHandler(page_id))
						.attr('href', opts.link_to.replace(/__id__/, page_id));
				}
				if (appendopts.classes) {
					lnk.addClass(appendopts.classes);
				}
				panel.append(lnk);
			}
			// 浜х敓"Previous"-閾炬帴
			if (opts.prev_text && (current_page > 0 || opts.prev_show_always)) {
				appendItem(current_page - 1, {
					text: opts.prev_text,
					classes: "prev"
				});
			}
			// 浜х敓璧峰鐐�
			if (interval[0] > 0 && opts.num_edge_entries > 0) {
				var end = Math.min(opts.num_edge_entries, interval[0]);
				for (var i = 0; i < end; i++) {
					appendItem(i);
				}
				if (opts.num_edge_entries < interval[0] && opts.ellipse_text) {
					jQuery("<span>" + opts.ellipse_text + "</span>").appendTo(panel);
				}
			}
			// 浜х敓鍐呴儴鐨勪簺閾炬帴
			for (var i = interval[0]; i < interval[1]; i++) {
				appendItem(i);
			}
			// 浜х敓缁撴潫鐐�
			if (interval[1] < np && opts.num_edge_entries > 0) {
				if (np - opts.num_edge_entries > interval[1] && opts.ellipse_text) {
					jQuery("<span>" + opts.ellipse_text + "</span>").appendTo(panel);
				}
				var begin = Math.max(np - opts.num_edge_entries, interval[1]);
				for (var i = begin; i < np; i++) {
					appendItem(i);
				}

			}
			// 浜х敓 "Next"-閾炬帴
			if (opts.next_text && (current_page < np - 1 || opts.next_show_always)) {
				appendItem(current_page + 1, {
					text: opts.next_text,
					classes: "next"
				});
			}
		}

		//浠庨€夐」涓彁鍙朿urrent_page
		var current_page = opts.current_page;
		//鍒涘缓涓€涓樉绀烘潯鏁板拰姣忛〉鏄剧ず鏉℃暟鍊�
		maxentries = (!maxentries || maxentries < 0) ? 1 : maxentries;
		opts.items_per_page = (!opts.items_per_page || opts.items_per_page < 0) ? 1 : opts.items_per_page;
		//瀛樺偍DOM鍏冪礌锛屼互鏂逛究浠庢墍鏈夌殑鍐呴儴缁撴瀯涓幏鍙�
		var panel = jQuery(this);
		// 鑾峰緱闄勫姞鍔熻兘鐨勫厓绱�
		this.selectPage = function (page_id) {
			pageSelected(page_id);
		}
		this.prevPage = function () {
			if (current_page > 0) {
				pageSelected(current_page - 1);
				return true;
			} else {
				return false;
			}
		}
		this.nextPage = function () {
			if (current_page < numPages() - 1) {
				pageSelected(current_page + 1);
				return true;
			} else {
				return false;
			}
		}
		// 鎵€鏈夊垵濮嬪寲瀹屾垚锛岀粯鍒堕摼鎺�
		drawLinks();
		// 鍥炶皟鍑芥暟
		opts.callback(current_page, this);
	});
}